A. \(33\frac{2}{6}\)
B. \(36\frac{8}{3}\)
C. \(34\frac{4}{2}\)
D. \(31\frac{5}{7}\)
Answer:
D. \(31\frac{5}{7}\)
Solution:
\[\left. \begin{array}{l}\\ { \text {Sum of the Ages of Grand Parents:}}\\ { \text {Avg Age=}}\frac{\text {Sum of Ages}}{\text {Total Persons}}\\ 67=\frac{\text {Sum of Ages}}{2}\\ \text {Sum of Ages}=67\times2=134 …(a)\\ { \text {Sum of the Ages of Parents:}}\\ =35\times2=70 … (b)\\ { \text {Sum of the Ages of Children:}}\\ =6\times3=18 ….(c)\\ { \text {Total Family Members:}}\\ =2+2+3=7 ….(d)\\ { \text {Average Age of family=}} (\frac{\text {Sum of the Ages}}{\text {Total Persons}}) \\ { \text {Average Age of family=}} (\frac{a+b+c}{d}) \\ { = ( \frac { 134 + 70 + 18 } { 7 } ) }\\{ = \frac { 222 } { 7 } }\\{ = 31 \frac { 5 } { 7 } \text { years. } }\end{array} \right.\]